Slop in factory plastic tail grips - how have you dealt with it?

[Bob O]

Originally Posted by Bob O

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FWIW, the stock tail is performing well for me so far. I just don't like slop. When I repaired the 6HV two weeks ago with a whole new tail using all stock parts, there was no slop. Ten flights later there is significant slop.
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I didn't want to derail my own thread on a possible new factory tail, so I'm starting this one.

First I have to say that the 6HV is still putting a smile on my face. I have about 70 flights on it since building it this summer. It's definitely a winner! However, if there is one thing I've never been a fan of, it's slop.

When I first built the 6HV, the plastic tail was without noticeable slop, however there quickly became a significant "wiggle" in the tail blade grips after only a short time. This did not seem to affect performance.

I had a crash a few weeks ago, and the entire tail section, not counting the tail case, was rebuilt with new parts. The new tail went together very well, and had no slop at all, which I was very happy with. However, after about only ten flights, the blade grips developed slop again, this time more than the original tail.

I arrived at the field today to get in some good flying. Putting the bird through my usual routine of fast backwards upright and inverted, and tail down funnels, there was oscillation in the tail that I had not seen with this bird. I landed and turned the tail gain down one point and took off again. The oscillation was mostly gone. I ended up flying the rest of the pack and then slapped on some new batts for a second flight.

My friend Nate arrived about halfway through my second flight. After I landed and had the heli on the bench, Nate noticed that my tail case was not squared up. I told him that my belt seemed somewhat loose today, but I hadn't noticed the tail case being out of whack. So I proceeded to eyeball the tail case/ TR shaft from the rear, and could see that it was slightly off. Being that the tail case is pinned, the boom obviously rotated in the boom block, which made sense as to the belt being loose. Looking into the tail case from the rear, I was able to see that belt coming off the pulley at the bottom was resting on the inside of the boom.

So I proceeded to pull out the boom, tighten the belt and realign the tail case, and got everything cinched back up. During this time, Nate commented to me that my tail was making a lot of noise during the funnels, more than what he had ever heard from it. That's when I showed him the slop in the blade grips, and he suggested that something might have come loose inside the grips. Being that there are nylock nuts on the tail hub, I told him that it was not likely that they had come loose, but I would check anyway.

I took one blade off and then split the blade grip to access the internals. I have to admit that this is a very nice feature of the current design. Once one half of the grip was off, I used the other half to move in an out to see where the slop was coming from. There was A LOT of movement of the thrust bearing stack within it's "pocket" in the blade grip. I tried tightening the nylock nut and found that it was still tight and couldn't get tightened any further. Where did all this space come from if it wasn't there when it was brand new? The only thing we could come up with was that the plastic had compressed over time, albeit only ten flights worth.

So I decided to look through my field/tool box to see if I had any washers that would fit the shaft AND take up the space in the blade grip pocket. Sure enough I found two identical washers that fit perfectly. I put these washers on the hub side of the thrust bearing stack and then reassembled the blade grips. Result? Slop was totally eliminated! Results in the air? The tail was the quietest it has ever been, and the performance was exceptional. Nate commented that he couldn't believe the difference from one flight to the next just by removing slop from the blade grips. Oh and tightening the belt. He attributed the problem to the slop in the tail, not from the loose belt, and I tend to support that.

I don't know the size of the washers I used, but I'll pull them out tomorrow and measure, take some pics, etc. Now I'm kind of wishing I hadn't just ordered the RJX tail rotor assembly. I don't know if the tail will develop more slop over the course of the next ten or twenty flights. I would like to think that the plastic won't keep wearing/ compressing like it seemed to have done up to this point.

Bottom line......all it took was a thin washer to take up the space in the thrust bearing pocket to eliminate the slop that had developed, and confidence in the tail has been restored.

[Rob43]

Very interesting, Bob O. I hate to say this, but I am on the original tail that came in the kit that I bought in the winter of 2010/2011 and have flown since spring of 2011. I can't say I've noted any developed slop. In fact, I used to note that my tail would not pyro against the torque and wind combined when flying at top speed. I attributed this to simply not having enough tail power to overcome the two until speed scrubbed off. Now, no changes and two season later, it has no such problem. In fact, I am very confident in saying it's tail is better than it was new in every way. It survived a crash this spring. Was untouched, though the front of the frame took the hit.

The RJX tail bits are very nice - I think you will be pleased with them. Seemed to work great on my 7HV. I used the stock slider - just used grip balls that had proper spacing when attached to the grips to make them align to the pitch links precisely. Very smooth, bind free tail. No slop.

[leaverus]

i haven't noticed much slop either.

[Bob O]

I'll have a video up shortly.

Sent from my phone

[Bob O]

If anyone cares to watch.

I'm headed to work shortly. Catch up with you guys later!

[leaverus]

that is a lotta slop - mine doesnt have that and it's almost 2 years old with original parts. of course, i probably put nowhere near the same stress on my heli as you. i originally thought you meant rotational slop in the grips and i see in your video it's axial slop. i'm a little confused why that should matter as long as everything is tight. when the tail is spinning, doesn't the centrifugal force keep the grips maximally displaced anyway?

[Carpediemkayaker]

Great Vid & Great Flying Yesterday Bob.

I'm still amazed at how the tail performed from one flight to the next when you did this slight modification. It was nice to see all your tail wag issues go away in an instant and have the tail perform amazingly through your whole flight like it originally did when it was brand new.

Also the fast backward to tail down funnel was silky smooth in my opinion. The tail didn't struggle or blow out at all, it was just great.

Hope to get out flying with you again soon.

-Nate

[Ah Clem]

Nicely done Bob!

Mine is several years old and has quite a bit of time on it. I was planning on going over it prior to the HF Fun Fly (it has to fly perfectly for the Fun Fly).

I will be examining the tail very closely and, if it has developed any slop, will follow your advice.

[Bob O]

Thank you, Sir. You, Will and others are a tough act to follow. I always try to do my best with whatever heli I have. The 6HV will last me for more than a single season I'm sure. I went through my last three nitro 50's pretty quickly. This heli is a keeper!

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[Rodney Kirstine]

I just checked mine and it's actually worse than what you show in that video, Bob. Ewww...

[wbefield]

Mine has alot of slop too even when new. I was going to shim my tail up last nite, but I couldn't find the appropriate washers.

[Bob O]

Yeah, I don't even know where the ones I used came from, probably one of my old 450 head parts. If it was a washer, screw, nut, spacer from a crashed bird, I ended up keeping them. I have quote an assortment of stuff in my field box...lol.

But I couldn't find the 4x9 washer in the hardware list on Nankin's site. I'm sure they can be found elsewhere, I just haven't had a chance to look around.

If you guys have that much or more slop in your tails, you might be surprised at the difference it makes in the air when things are tightened back up. If I end up finding the proper size washer, I'll post the info.

Sent from my phone

[Inverse]

I too am a hater, of slop. Part of the reason I don't fly Align anymore.
Thanks, Bob. I'll see if mine gets the same slop over time.

[Inverse]

Originally Posted by leaverus

that is a lotta slop - mine doesnt have that and it's almost 2 years old with original parts. of course, i probably put nowhere near the same stress on my heli as you. i originally thought you meant rotational slop in the grips and i see in your video it's axial slop. i'm a little confused why that should matter as long as everything is tight. when the tail is spinning, doesn't the centrifugal force keep the grips maximally displaced anyway?

Yes, but axial slop will also contribute to radial slop due to the pockets being oversized.

[Bob O]

Yes, there was slop both ways, though mostly in and out like in the video. The other slop it had, although not as much of it, was the "wiggle" I described. That must be what you guys are referring to as radial slop.

I have to do some other things this morning yet, so I haven't had a chance to search for the 4x9x0.3 or other thickness washers.

[Rodney Kirstine]

There are some 4x8x0.3 here:

http://www.mcmaster.com/#catalog/118/3246/=jay7uk

[Larry227]

I have around 50+ flights on mine and just checked it, one grip has a small amount of axial slop and the other is still tight. I'll check it out sometimes in the future since it's down for awhile anyways.

[Bob O]

Originally Posted by Knuckledragger

There are some 4x8x0.3 here:

http://www.mcmaster.com/#catalog/118/3246/=jay7uk

Thanks Kd for the find. Nice to have thinner options in case a person wants to do this but doesn't have as much slop as mine did.

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[sarpilot]

Nice vid Bob. Mine has always had that axial play I just always thought that was how it was and centrifugal force would eliminate it in flight. Something else to repair now… :eek:
Thx for the tip


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[Bob O]

Yeah, but its a quick and easy job.

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